Dallas Area Rapid Transit will soon begin running beer and wine ads on buses and trains, two years after the agency’s board reversed a long-standing policy against such displays.

And just like back in 2011, the motivation is cash.

DART officials predict that beer and wine ads could bring in an additional $400,000 annually. That’s a pittance compared with the $60 million in fares or $435 million in tax dollars that the agency brought in last year.

DART hit a bump in the road two years ago, after board members approved the ads. The agency OK’d just one such set of ads — for Victoria beer, officials recalled — before the Texas Alcoholic Beverage Commission stepped in. The commission said state law appeared to prohibit the ads. There was ambiguity over whether transit buses and trains were “vehicles for hire” and what constituted outdoor advertising.

The Legislature this year clarified those issues for DART and other agencies with a bill co-written by Rep. Charlie Geren, R-Fort Worth.

On Tuesday, DART staff members will update the board on the rollout of beer and wine ads. Officials predict that alcohol ads will become the agency’s fourth-biggest advertising category, behind media, telecommunications and education.

DART has long been reluctant to accept such advertisements, given that much of the agency’s early efforts to encourage ridership involved outreach through schools and churches. But the revenue potential proved too great.

Nevin Grinnell, DART’s chief marketing officer, said the agency will encourage ads that ask consumers to drink responsibly. The agency will require that the ads be distributed evenly throughout the service area so that some neighborhoods don’t end up with a glut.

And DART is looking at ways to use the advertisements to promote mass transit as a safe alternative to driving to ballgames, concerts and other events where alcohol is served.